Abstract: This paper describes the inversion of gravity anomaly using Parker-Oldenburg method briefly,and analyzes the effects of different thresholds of low-pass filter on the separation of the gravity field.The Bouguer gravity anomaly in Tibetan Plateau is decomposed by wavelet transform and low-pass filter respectively,and applied to the inversion of Moho.Comparing inverted Moho interface from wavelet transform and low-pass filter with that from seismic source,it can be concluded that the multi-scale decomposition of wavelet is able to substitute low-pass filter B(K) and avoid choosing the threshold of the low-pass filter in the decomposition of the gravity field.